Solution for rust-proofing articles of iron and steel.



manganese dioxid, l tenths of one per cent, and the metallic ENT OFFICE.

WILLIAM H. ALLEN, 015 DETROIT, MICHIGAN, ASSIGNOR TO PARKER RUST PROOFCOM- I UT AMERICA, 01'! DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

SUIJUTION FOR RUST-PROOIFING- ARTICLES OF IRON AND STEEL.

res ate.

No Drawing.

To all whom it may concern Be it known that I, WrLLIAM H. ALLEN, a

citizen of the United States, and residing at Detroit, in the county ofWayne and State of Michigan, have invented a new and Improved Solutionfor Rust-Proofing Articles of Iron and Steel, of which the following isa specification. This invention relates to re rust-proofing of surfacesof iron and steel, .and its object is to provide a material which willbe most efl'ective for this purpose.-

This invention consists in combining a small percentage of zinc' in theform of metal, oxid or phosphate with an intensifying agent such as amaganese oxid, and phosphoric acid dissolved in Water, into whichsolution the articles to be treated are kept immersed for several hours,the bath being at a boiling point.

It has been found that the surfaces of the articles treated in this bathbecome blacker and are more resistant to the action of the treatedbefore chemical equilibrium is established.

I The preferred proportions of the bath are: water, one hundred parts,phosphoric acid, approximately five-tenths of one per cent,

approximately four- Speciflcation of Letters Patent. Patented Jan, 14,1919,

Application filed January 11, 1917. Serial No. 141,803.

equivalent of zinc, from one to ten per cent. of the Weight of themaganese dioxid. The

larger amount of the zinc gives more pronounced results, but theaddition of the smaller minute amount is beneficial. The proportions ofacid and manganese oxid may be varied through quite wide limits.

It seems to be quite clearly established that the action of the acid onthe iron and steel is to form ferrous phosphate, and that the manganesedioxid is oxygen bearing and gives up oxygen to some of the ferrous phosphate, changing it to ferric phosphate. These ferric and ferrousphosphates are probably formed at the surface of the metal being treatedand while in the nascent state unite with the metal to produce a blackrust-proof surface. Any oxygen bearing compound of a metal such aspotassium, sodium, calcium, barium, strontium or manganesium chromate,dichrom'ate, manganate or permanganate may be substituted for themanganese dioxid, although the expense connected with the use of theothers is greater'in some cases prohibitive.

I claim I l. A solution for rust-proofing the surfaces of iron and steelconsisting of a solution in water of phosphoric acid, manganese dioxidand zinc.

2. A solution for rust-proofing surfaces of iron and steel consisting ofa solution in water of phosphoric acid, an oxygen bearing compound of ametal, and zinc.

WILLIAM H. ALLEN.

